The present invention relates generally to the field of keyboard devices and, more particularly, to keyboard devices that are able to reduce the occurrence of undesired sounds when pressing keys along with being able to provide a secure attachment of a cover plate to a base.
Japanese Examined Patent 1974-35209 discloses use of a hard material to increase the strength of the keys. When pressed by a musical performer, if coarse material was used to increase the absorbency, there was a problem in that the keys were weak.
The surface material (plate) submerged into absorption fluid is affixed to the key (base) surface using an adhesive. The key affixes the surface material with a different characteristic than the key surface, as described in Japanese Unexamined Patent 1995-44156.
However, the key affixed to both the base and the plate was pressed excessively by performers, and if it continued for a long period of time after being affixed, the strength of the adhesive could wear off, and the plate could become loose.
Also, because the adhesive is applied between the base surface and the plate surface, if the adhesive is not evenly distributed, one area can become loose, leaving an empty space between the base and the plate. When this empty space occurs, an undesired noise can occur when the performer touches the keys, and this may confuse the performer.